The present invention relates generally to semiconductor device fabrication and, in particular, to device structures for tunnel field-effect transistors, fabrication methods for tunnel field-effect transistors, and design structures for tunnel field-effect transistors.
Field-effect transistors are widely used in the electronics industry for switching, amplification, filtering, and other applications related to both analog and digital electrical signals. Complementary Metal Oxide Semiconductor (CMOS) technology, which is the prevailing technology used in integrated circuit fabrication, integrates n-channel and p-channel field-effect transistors to fabricate logic and other circuitry. The most common CMOS technology is based upon silicon.
Continuing trends in semiconductor device manufacturing include reduction in electrical device feature sizes (i.e., scaling), as well as improvements in device performance in terms of device switching speed and power consumption. The performance of field-effect transistors may be improved by reducing the distance between the source and drain, and by reducing the thickness of the layer of gate dielectric. However, there are electrical and physical limitations on the extent to which these parameters may be scaled. As scaling of silicon-based CMOS technology approaches its physical limit, the demand for energy efficient, high-speed and highly compact computing technology has accelerated the search for an alternative.
One such alternative is a tunnel field-effect transistor, which is based on ultrathin films and band-to-band tunneling in which a valence band electron tunnels across the band gap to the conduction band without the involvement of traps. Tunnel field-effect transistors may exhibit a reduced power dissipation compared to CMOS field-effect transistors, thus making tunnel field-effect transistors a promising successor to traditional CMOS field-effect transistor.
Improved device structures, fabrication methods, and design structures are needed for tunnel field-effect transistors.